<article class="" id="post-">
<header class="entry-header">
<h1 class="entry-title">:focus Selector</h1>
<div class="entry-meta">
						所属分类：<span class="category"><a href="/category/selectors/">选择器</a> &gt; <a href="/category/selectors/basic-filter-selectors/">基础过滤</a></span><span class="category-divider"> | </span><span class="category"><a href="/category/selectors/">选择器</a> &gt; <a href="/category/selectors/form-selectors/">表单</a></span>
<span class="pull-right">英文文档：<a href="https://api.jquery123.com/focus-selector/" target="_blank">:focus Selector</a></span>
</div><!-- .entry-meta -->
</header><!-- .entry-header -->
<!-- .entry-header -->
<div class="entry-content">
<article class="entry selector" id="focus1"><h2 class="section-title"><span>focus selector</span></h2>
<div class="entry-wrapper">
<p class="desc"><strong>描述: </strong>选择当前获取焦点的元素。</p>
<ul class="signatures"><li class="signature"><h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.6/">1.6</a></span>jQuery( ":focus" )</h4></li></ul>
<div class="longdesc" id="entry-longdesc">
<p>如同其他伪类选择器（那些以":"开始）一样，使用<code>:focus</code>时，建议在他们前面加一个标签名称或其他选择;否则，会使用默认的通用选择器("*")，性能是不言而喻的。换句话说，<code>$(':focus')</code>等同为<code>$('*:focus')</code>。如果你正在寻找当前的焦点元素，<code>$( document.activeElement )</code>将检索，而不必查找整个DOM树。</p>
</div>
<section class="entry-examples" id="entry-examples"><header><h2 class="underline">例子:</h2></header><div class="entry-example" id="example-0">
<h4><span class="desc">给获取焦点的元素添加focused类</span></h4>
<div class="syntaxhighlighter xml ">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
<div class="line n12">12</div>
<div class="line n13">13</div>
<div class="line n14">14</div>
<div class="line n15">15</div>
<div class="line n16">16</div>
<div class="line n17">17</div>
<div class="line n18">18</div>
<div class="line n19">19</div>
<div class="line n20">20</div>
<div class="line n21">21</div>
<div class="line n22">22</div>
<div class="line n23">23</div>
<div class="line n24">24</div>
<div class="line n25">25</div>
<div class="line n26">26</div>
<div class="line n27">27</div>
<div class="line n28">28</div>
<div class="line n29">29</div>
<div class="line n30">30</div>
<div class="line n31">31</div>
<div class="line n32">32</div>
<div class="line n33">33</div>
<div class="line n34">34</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code><span class="doctype">&lt;!DOCTYPE html&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">html</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">style</span>&gt;</span><span class="css"></span></code></div></div><div class="container"><div class="line"><code><span class="class">.focused</span> <span class="rules">{</span></code></div></div><div class="container"><div class="line"><code>    <span class="rule"><span class="attribute">background</span>:<span class="value"> <span class="hexcolor">#abcdef</span>;</span></span></code></div></div><div class="container"><div class="line"><code><span class="rule">}</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">style</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"https://code.jquery.com/jquery-latest.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">div</span> <span class="attribute">id</span>=<span class="value">"content"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">input</span> <span class="attribute">tabIndex</span>=<span class="value">"1"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">input</span> <span class="attribute">tabIndex</span>=<span class="value">"2"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">select</span> <span class="attribute">tabIndex</span>=<span class="value">"3"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>        <span class="tag">&lt;<span class="title">option</span>&gt;</span>select menu<span class="tag">&lt;/<span class="title">option</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;/<span class="title">select</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">div</span> <span class="attribute">tabIndex</span>=<span class="value">"4"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>        a div</code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;/<span class="title">div</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">div</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span>&gt;</span><span class="javascript"></span></code></div></div><div class="container"><div class="line"><code>$( <span class="string">"#content"</span> ).delegate( <span class="string">"*"</span>, <span class="string">"focus blur"</span>, <span class="keyword">function</span>( event ) {</code></div></div><div class="container"><div class="line"><code>    <span class="keyword">var</span> elem = $( <span class="keyword">this</span> );</code></div></div><div class="container"><div class="line"><code>    setTimeout(<span class="keyword">function</span>() {</code></div></div><div class="container"><div class="line"><code>       elem.toggleClass( <span class="string">"focused"</span>, elem.is( <span class="string">":focus"</span> ) );</code></div></div><div class="container"><div class="line"><code>    }, <span class="number">0</span>);</code></div></div><div class="container"><div class="line"><code>});</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">html</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<h4>Demo:</h4>
<div class="demo code-demo"></div>
</div></section>
</div></article> </div>
</article>